SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24b6336f75001af0e4060375561bdd357627421e2a34166b5abe3c93d1d924d3' 
  AND token = 'eYjl353niEblpcXXYs/3xfweoT1zMESxi3ng2mAhaD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}